Diagnostic instrument for eye examinations



July 16, 1935. J PASCAL 2,008,224

DIAGNOSTIC, INSTRUMENT FOR EYE EXAMINATIONS Filed Odt. 14, 1933 -,2 Sheets-Sheet 1 1N VENTOR.

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July 16, 1935. J. l. PASCAL DIAGNOSTIG INSTRUMENT FOR EYE EXAMINATIONS Filed Oct 14, 1933 2 Sheets-Sheet 2 INVENTOR.

Patented July 16, 1935 UNITED STATES DIAGNOSTIC INSTRUMENT FOR; EYE

. EXAMINATIONS Joseph Irving Pascal, New York, N. Y.

Application October 14, 1933, Serial No. 693,616 I 6 Claims. (01. ss-2o) My invention which is a diagnostic instrument for eye examinations relates to improvements in the art of examining eyes by means of crosscylinders. It is designed to make the cross-cyl- 5 incler testseasier, quicker, and much more accurate. The main feature of it is that it'provides a handy, compact, partly automatic device for manipulating cross-cylinders so that the,

Amongst other things it is used for determining:'

(a) The presence of astigmatism (b) The correct axis of the required cylinder (0) The exact strength of the requiredcyl inder.

The present method of, making these tests is to hold the ordinary cross-cylinder by its handle, usually between thumb and forefinger of the right or left hand, about an inch or so in front of patients eye or trial lens, align its axis as best one can with the axis, marks on the trial cell behind it, and to rapidly rotate the cylinder through an angle estimated to be 180 degrees, by a swift turn of the handle.

Some of the difficulties and inaccuracies which are inherent in the cross-cy1inder tests as a result of uncontrolled and unsupported manipulations of the ordinary cross-cylinde13 are described in the following paragraphs.

I. It is essential for the accuracy of thetest whatever it be used for, that the turning of the cross-cylinder be exactly 180 degrees so that the plane of the cross-cylinder both in the first and second position, is parallel to the plane of the trial-lens;

between the fingers of one hand is stopped only by the examiners judgment and muscle sense.

There is nothing to stop the movement at the 180 degree turn or any other position. The examiner can only judge by inspection whether or not he has turned the cylinder too much or too little. And as the essence of the test is to obtain a quick toand-fro rotation of exactly 180 degrees, it is evident that this is impossible by uncontrolled finger rotation. Subsequent inspection and judgment of the accuracy of the turning is of no value even if the examiner can accurately judge a deviation from the 180-de grees required. For, rectification of the turning It is practically impossible to attain such accuracy since the turning as carried out to make it exactly.l degrees if it was judged excessive or deficient, is of no use since the patients reaction to the change had already taken place during the initial, quick rotation.

Thus it is practically impossible. by the present method of rotating the cylinder by the feel of the fingers of one hand, supplemented by judgment and inspection, to obtain an accurate rapid rotation of degrees.

II. It is necessary for the accuracy of the crosscylinder tests that the cross-cylinder lens be properly centered with the eye or with the trial lens. Otherwise, undesirable, prismatic effects enter into the tests. But it is practically impossible to maintain such centering of crosscylinder lens and trial lens throughout the various manipulations when the cross cylinder is held before the eye without a fixed support.

III. It is necessary for the accuracy of the cross-cylinder tests that the plane of the cross cylinder be parallel to the plane of the trial cylinder in the initial and final stage of the rotation. But it is practically impossible to maintain such parallelism of planes throughout the various manipulations, when the cross cylinder is held before the eye without fixed support.

IV. It is essential when using the cross cylinder to determine the amount of astigmatism or check the accuracy of the cylinder before patients eye that the axis (either plus or minus) 0f the cross-cylinder be placed in exactly the same position as the axis of the trial cylinder, With the cross-cylinder as now used without a surrounding axis dial, the cross cylinder axis position is set by the examiner aligning its axis with reference to an axis dial on the trial cell, an inch or so further back. To get even an approximate judgment of alignment it is often necessary for the examiner to stoop and strain in an awkward position in order to place his eye on a level with the patients eye. Furthermore, the axis marks on the trial cell, in trial frame, phoroptor, refractor, or similar apparatus for holding trial lenses are necessarily small and are represented by thin lines, making alignment from a distance especially uncertain, and still more so, at the unnumbered axis lines. s

But even if the cross-cylinder axis and trial cylinder axis are initially aligned correctly, in the process of rotating the cross-cylinder to-and-iro,

. its axis is bound to be thrown more or less out of alignment due to the practical impossibility of holding the hand, arm, fingers and cross-cylinder handle absolutely steady during the rotations. For examiners whohave a slight unsteadiness of ference between the corrections for the two eyes.

V. It is absolutely essential when the cross-cylinder is used to check the accuracy of the required cylinder axis and to rectify any inaccuracy, that the cross-cylinder be placed with its axis (plus and minus) alternately at an angle of exactly 45 degrees to the axis of the trial cylinder. This axis position must be maintained during the repeated to-and-fro rotations of the cross cylinder lens through an'angle of 180 degrees. A maladjustment or a shift during the processof rotating the cross cylinder of even a few degrees practically vitiates the value of the test. Due to the uncertainty of exact alignment of the axes all through the test, the examiner can never accurately evaluate the patients reactions during the test nor properly interpret variations in the patients answers. Furthermore, exact alignment and-absolute steadiness is required in this test with each change inposition of the trial cylinder.

This is a procedure practically impossible of accurate execution'with an unsupported cross-cylinder held and rotated between the fingers of one hand its axis position located by visual judgment of alignment from a dial some distance behind it, without provision for maintaining the same axis position throughout the tests, and

7 without provision for accurately stopping the rotation after each turn of 180 degrees.

The'object of my invention is to remove these difiiculties and inaccuracies in cross-cylinder testing. Briefly the purposes of my invention are:

. (1) To secure and maintain correct centering and steadiness of the cross cylinder lens during the several tests in which it is employed.

(2) To secure and maintain parallelism of the plane of the cross-cylinder lens with the plane of the trial lens during the several tests in which it is employed.

(3) To enable the examiner to place the cros cylinder axis or handle exactly at the axis position desired.

(4) To enable the examiner to retain the same axis position of' the cross-cylinder lens all through the manipulations of the cross-cylinder lens in the process of testing.

(5) To enable the examiner tomake a rapid to-and-fro rotation of the cross-cylinder lens through an angle of exactly degrees, thus reversing its surfaces, and doing so with the same accuracy as many times and as slowly or rapidly as he chooses.

(6) To enablethe examiner to obtain all the aformentioned advantagesby the use of a single complete instrument and a few auxiliary, interchangeable double-shaft cross-cylinder lenses. Other purposes and advantages of the instrument reside in the detail construction of the instrument, which is designed for simplicity, economy and efliciency.

The characteristics and advantages of the invention are sufficiently explained 'in the accompanying drawings which show a preferred embodiment of the invention. Skilled persons will understand that many. variations may be made Fig. 4 is a front view of the supporting disc or frame;

Fig. 5 shows'a vertical cross section through Fig. 4.

Fig 6 is a rear view of lens holding ring.

Fig. 7 shows a vertical section through the center of Fig. 6.

Fig. 8 shows a rear view of the collar ring.

Fig. 9 shows a vertical cross section through center of Fig. 8.

Fig. 10 is a face View of the double-shaft cross cylinder.

Fig. 11 is a side view of Fig. 10; V

Fig. 12 is a front View of another form of my invention.

Fig. 13 shows a cross section throughfthe center of Fig. 12.

Fig. 14 shows a rear view of Fig. 12.

Fig. 15 is a front view of supporting disc or frame.

Fig. 16 is a vertical section through the center of Fig. 15.

Fig. 17 is a rear view of lens-holding ring. Fig. 18 shows a vertical section through the center of Fig. 17.

Fig. 19 is a face view of the double-shaft cross cylinder. 1

Fig. 20 is a side view of Fig. 19.

Fig. 21 is an enlarged, view of method of attaching and detaching one end of cross cylinder to lens-holding ring.

Fig. 22 shows enlarged detail of method of attaching or detaching other end of cross cylinder to lens-holding ring;

Figures 1-11 illustrate one form of my invention. a

Fig.1 is a front view of the complete assembly. Fig. 2 is a side view. The assembly comprises a disc or frame I, having a shank or extension 2 and carrying a calibrated dial 3 marked off in degrees. Fastened to the shank 2 is a projection 4 preferably tubular which may be attached to a phorooptometer, phoroptor, refractor, etc. These parts are shown in detail in Figures 4 and 5.

The disc 'I is designed to retain a lens-holding rotating ring 5 carrying a cross-cylinder 1. Ring 5 is held secure in disc'or frame I on the'front side preferably by means of a concentric depression 6 in disc I, Figures 4 and 5, and a correspending shoulder IS in ring 5, Figures 6 and 7, thus preventing'ring 5 from slipping backwards. Ring 5 is held securely to disc I on the rear side, preferably by a collar ring [3, which is snugly clamped over ring 5, Figures 2, 3, 8 and 9. Ring 5 may be held in disc I in other ways as for instance by means of several small overlapping discs fastened securely to ring 5 and gliding freely over adjacent margin of disc I.

Set in ring 5 is a cross cylinder 7 which rotates with ring 5 in frame I and which can be quickly flipped back and forth within ring 5, through an angle of 180 degrees, determined preferably by finger or abutment l2 hitting against frame I after a rotation of 180 degrees either way, Fig. 3.

Figures 10 and 11 show in detail cross cylinder 1 atone end of which is a projection or shaft 8,

III

which fits into a groove or bearing 9 inlensholding ring 5, Figures 6 and 7', and at the opposite end of which iscanother projection or shaft II! which fits. into groove orbearingII in ring 5, Figures 6-.and 'i and which may-serve as a handle for rotating lens-holding. ring 5 disc I,.Fig; 1. and for flipping cross-cylinder .I back and forth about an axis formed by shafts 8' and It resting against: disc I, Fig. 3.. To limit this back and forth rotation to 180 degrees '15 preferably place a finger or bar .or similar abutment I2 extending from shaft I and parallel to plane of cross cylinderl'ens which acts as an automatic stop after each: rotation of 180 degrees'back or forth by striking against disc I, Fig; 3."

-Figures 8 and '9 showin detail collar ring I3. This ring. is snugly clamped over rear surface of ring 5 as shown inlFig. 2, thus holding ring 5 securely. against frame I;\ Collar I3 rotates with ring 5 within disc I.. A slot I4 is cut into collar I3, Figuresfi and 9 to correspond toslot II in ring 5, Figures 6 and 7, thus forming a bearing for shaft: I 0'. A similar slot I5 is cut diametrically opposite to I4 on collar ring I3 to correspond to slot 9 in ring 5, Figures 6 and '7, thereby forming a bearing for shaft 8, Fig. 2.

Figures 12-22 illustrate another form of my invention. Fig. 12 is a front view of a complete assembly. Fig. 13 is a cross section of Fig. 12. The assembly comprises disc I, having a shank or extension 2 and a projecting arm 4 into which is fitted a brow rest I I. The brow rest I! is preferably made adjustable to different distances from the brow by sliding in sleeve 4. Or the brow rest may be made of one fixed length extending directly from shank 2.

Disc I has a calibrated dial 3, Fig. 15 and carries a rotating lens-holding ring 5, Figures 13 and I4. Ring 5 is held in disc I on the front surface preferably by a shoulder I6 in ring 5, Figures 17 and 18, resting against a depression 6 on the front surface of disc I, Figures 15 and 16, and on the rear surface preferably by shafts 8a and I8 securely held against ring 5 by springs I 8 and 22 and. projecting beyond ring 5 to rest on disc I, Figures 13 and 14. Ring 5 while securely held in disc I can rotate freely within disc I, preferably by using I0 as a grip for such rotation, Figures 13 and 14. V

Ring 5, Figs. 13 and 14 carries cross cylinder I attached to it at one end preferably by means of a spring I 8 resting over shaft 8a. and at the other end by a sliding spring catch or hearing cap 22 Y resting over extremity of shaft I 0. Spring I8 preferably works in a slot l9, Fig. 21 so as to allow shaft 8a to be easily pushed under it when inserting cross-cylinder lens. Sliding spring 22 rotates on pivot 25, Fig. 22 allowing spring to cover or expose extremity of shaft ID or groove I I. Turning spring 22 to expose shaft I9 permits easy removal of cross-cylinder lens. To hold crosscylinder in position spring 22 is rotated to pass over shaft I0 and preferably hooked under headed post or peg 25, Fig. 22. This arrangement holds ring 5 and contained cross-cylinder I securely against disc I and permits a rapid interchange of cross-cylinder into ring 5. Releasing and turning to one side sliding spring catch 22 enables the examiner to remove cross-cylinder by simply drawing it out from under spring I8. To insert cross-cylinder sliding spring 22 is rotated to expose slot II, shaft 8a is pushed under spring I8 and sliding spring 22 is passed over shaft III and preferably hooked under peg 25. Cross cylinder I may also be attached to ring 5 by two sliding springs which open and close over shafts 8c and Ill. Figs. 21 and 22. show an enlargedand detailed view of one preferred mode of attaching crosscylinder I to ring 5 so that they can be quickly and easily detached and as quickly and easily reattached. A barorspring' I8, Fig. 21 is fastened at one end on one side of groove 9 to ring 5, preferably by'a screw or rivet 2B, and at the other end on the other side of groove 9 by another screw or rivet 2 I preferably lodged in a slot I9. Spring I8 converts groove 9, Fig. 17 into a bearing for shaft 8a into which the shaft M can be quickly pushed in and from which it can be quickly pulled out. a The part of shaft 8a projecting beyond ring 5 helps to keep r'ing 5 against disc I, Fig. 14.

A sliding spring catch or bearing cap 22, Figj 22 isfastcned at one end on one side of groove I I to ring 5 by means of pivot 24 on which it can rotate. 'At the :other free end on the other side of groove II a peg or similar headed post is fastened into a ring 5 so that sliding spring 22 can slide under its head, preferably by means of groove 23. When thus closed spring 22 converts groove II, Fig. 17 into a bearing for shaft I0 and holds shaft Ill against ring 5 and by its extension also against disc I. When open, thatis when spring 22 is turned aside by rotating on pivot 24, it exposes shaft I0, and permits ready removal of cross-cylinder I. With cross-cylinder removed this open position exposes groove II into which shaft III of the same or other cross-cylinder can be quickly and easily inserted and held in place by sliding spring 22 over it.

Obviously, slight changes may be resorted to and I reserve the right to make such changes falling within the scope of the appended claims without departing from the spirit of my invention.

I claim: i

1. In an instrument for testing and measuring astigmatism, a supporting frame, a ring mounted therein and rotatably adjustable in the plane thereof, a cross-cylinder testing lens journaled in said ring for rotation about an axis in said plane, a handle rigidly secured to the lens in alignment with said axis of rotation and immovable with respect to the lens, and cooperating means between the lens and a fixed portion of the frame for limiting said lens rotation to an accurate 180, whereby a mere twirling of the handle will effect a rapid back-and-forth rotation of the lens between accurately delimited extremes.

2. In an instrument for testing and measuring astigmatism, a supporting frame, a ring mounted thereof, a cross-cylinder testing lens journaled in said ring for rotation about an axis in said plane, a handle rigidly secured to the lens in alignment with said axis ofrotation and immovable with respect to the lens, and cooperating means between the lens and a fixed portion of the frame for limiting said lens rotation to an accurate 180, whereby a mere twirling of the handle will effect a rapid back-and-forth rotation of the lens between accurately delimited extremes, said means comprising an abutment movable with the lens I and adapted to encounter the relatively fixed portion of the instrument when the lens is rotated into a position parallel to the plane of said frame.

3. In an instrument for testing and measuring astigmatism, a supporting frame, a ring mounted therein and rotatably adjustable in the plane thereof, a cross-cylinder testing lens journaled in said ring for rotation about an axis in said plane, a handle rigidly secured to the lens in therein and rotatably adjustable in the plane alignment with said axis of rotation and immovable with respect to the lens, and cooperating means'between the lens and a fixed portion of the frame for limiting said lens rotation to an accurate 180, whereby a mere twirling of the handle will effect a rapid 'back-and-forth rotation of the lens between accurately delimited ex-a tremes, said means comprising a lateral projection carried by saidhandle and adapted to encounter the frame when the lens is rotated into a position parallel to the plane of said frame.

4. In an instrument for testing and measuring astigmatism, a supporting frame, a ring mounted therein and rotatably adjustable in the plane thereof, a series of cross-cylinder testing lenses, and releasable means on the ring for interchangeably mounting any selected lens of said series in said ring for rotation about an axis in said plane.

5. In an instrument for testing and measuring astigmatism, a supporting frame, a ring mounted therein and rotatably adjustable in the plane thereof, a series of cross-cylinder testing lenses,

and releasable means 7 on the ring. for inter-- changeably mounting any selected lens of said series in said ring for rotation about an axis in said plane, said means comprising a pair of aligned bearings carried by said ring, and are movable cap for at least one of said bearings.

6. In an instrument for testing and measuring astigmatism, a supporting frame, a ring mounted therein and rotatably adjustable in the plane thereof, a series of cross-cylinder testing lenses, releasable means on the ring for interchangeably mounting any selected lens of said series in said ring for rotation about an axis in said plane, a handle rigidly secured to each lensin alignment with said axisof rotation and immovable with respect to the lens,'and cooperating 'means between the lens and a fixed portion of the frame for limiting said lens rotation to an accurate 180, whereby a mere twirling of the handle will effect a rapid back-and-forth rotation of the lens be 39 a tween accurately delimited extremes.

JOSEPH IRVING PASCAL. 

